Use of medium chain triglycerides for the treatment and prevention of Alzheimer&#39;s disease and other diseases resulting from reduced neuronal metabolism II

ABSTRACT

Methods and compositions for treating or preventing, the occurrence of senile dementia of the Alzheimer&#39;s type, or other conditions arising from reduced neuronal metabolism and leading to lessened cognitive function are described. In a preferred embodiment the administration of triglycerides or fatty acids with chain lengths between 5 and 12, to said patient at a level to produce an improvement in cognitive ability.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.11/021,920, filed Dec. 22, 2004, entitled “Use of Medium ChainTriglycerides for the Treatment and Prevention of Alzheimer's Diseaseand Other Diseases Resulting from Reduced Neuronal Metabolism II,” whichapplication is a continuation of U.S. application Ser. No. 10/152,147(now U.S. Pat. No. 6,835,750), filed May 20, 2002, entitled “Use ofMedium Chain Triglycerides for the Treatment and Prevention ofAlzheimer's Disease and Other Diseases Resulting from Reduced NeuronalMetabolism II,” which application is a continuation-in-part of U.S.application Ser. No. 09/845,741, filed May 1, 2001, entitled “Use ofMedium Chain Trigylcerides for the Treatment and Prevention ofAlzheimer's Disease and Other Diseases Resulting from Reduced NeuronalMetabolism,” which claims priority to U.S. Provisional Application Ser.No. 60/200,980 filed May 1, 2000, entitled “Use of Medium ChainTriglycerides for the Treatment and Prevention of Alzheimer's Diseaseand Other Diseases Resulting from Reduced Neuronal Metabolism,” each ofwhich are incorporated herein by reference in their entirety. Thisapplication also claims the benefit of U.S. Provisional Application Ser.No. 60/375,909, filed Apr. 26, 2002, entitled “The Effect of MediumChain Triglycerides on Memory in Mild Cognitive Impairment andAlzheimer's Disease,” which is incorporated herein by reference in itsentirety.

FIELD OF THE INVENTION

This invention relates to the field of therapeutic agents for thetreatment of Alzheimer's Disease, and other diseases associated withreduced neuronal metabolism, including Parkinson's disease, Huntington'sDisease, and epilepsy.

BACKGROUND OF THE INVENTION

Alzheimer's Disease (AD) is a progressive neurodegenerative disorder,which primarily affects the elderly. There are two forms of AD,early-onset and late-onset. Early-onset AD is rare, strikes susceptibleindividuals as early as the third decade, and is frequently associatedwith mutations in a small set of genes. Late onset, or spontaneous, ADis common, strikes in the seventh or eighth decade, and is amutifactorial disease with many genetic risk factors. Late-onset AD isthe leading cause of dementia in persons over the age of 65. Anestimated 7-10% of the American population over 65, and up to 40% of theAmerican population greater than 80 years of age is afflicted with AD(McKhann et al., 1984; Evans et al. 1989). Early in the disease,patients experience loss of memory and orientation. As the diseaseprogresses, additional cognitive functions become impaired, until thepatient is completely incapacitated. Many theories have been proposed todescribe the chain of events that give rise to AD, yet, at the time ofthis application, the cause remains unknown. Currently, no effectiveprevention or treatment exists for AD. The only drugs to treat AD on themarket today, Aricept®, Cognex®, Reminyl® and Exelon® areacetylcholinesterase inhibitors. These drugs do not address theunderlying pathology of AD. They merely enhance the effectiveness ofthose nerve cells still able to function and only provide symptomaticrelief from the disease. Since the disease continues, the benefits ofthese treatments are slight.

Early-onset cases of AD are rare (˜5%), occur before the age of 60 andare frequently associated with mutations in three genes, presenilin1(PS1), presenilin2 (PS2) and amyloid precursor protein (APP) (for reviewsee Selkoe, 1999). These early-onset AD cases exhibit cognitive declineand neuropathological lesions that are similar to those found inlate-onset AD. AD is characterized by the accumulation of neurofibrillartangles (NFT) and β-amyloid deposits in senile plaques (SP) and cerebralblood vessels. The main constituent of senile plaques is the β-amyloidpeptide (Aβ), which is derived from the APP protein by proteolyticprocessing. The presenilin proteins may facilitate the cleavage of APP.The Aβ peptide is amyloidagenic and under certain conditions will forminsoluble fibrils. However, the toxicity of Aβ peptide and fibrilsremains controversial. In some cases Aβ has been shown to be neurotoxic,while others find it to be neurotrophic (for reviews see Selkoe, 1999).The cause of early-onset AD is hypothesized to be accumulation ofaggregated proteins in susceptible neurons. Mutations in APP arehypothesized to lead to direct accumulation of fibrillar Aβ, whilemutations in PS1 or PS2 are proposed to lead to indirect accumulation ofAβ. How a variety of mutations in PS1 and PS2 lead to increased Aβaccumulation has not been resolved. Accumulation of aggregated proteinsis common to many progressive neurodegenerative disorders, includingAmyloid Lateral Sclerosis (ALS) and Huntington's Disease (for review seeKoo et al., 1999). Evidence suggests that accumulation of aggregatedproteins inhibits cellular metabolism and ATP production. Consistentwith this observation is the finding that buffering the energy capacityof neurons with creatine will delay the onset of ALS in transgenic mousemodels (Klivenyi et al., 1999). Much of the prior art on AD has focusedon inhibiting production of or aggregation of Aβ peptides; such as U.S.Pat. No. 5,817,626, U.S. Pat. No. 5,854,204, and U.S. Pat. No.5,854,215. Other prior art to treat AD include, U.S. Pat. No. 5,385,915“Treatment of amyloidosis associated with Alzheimer Disease usingmodulators of protein phosphorylation”, U.S. Pat. No. 5,538,983, “Methodof treating amyloidosis by modulation of calcium.” Attempts to increaseneuronal survival by use of nerve growth factors have dealt with eitherwhole cell, gene or protein delivery, such as described in U.S. Pat. No.5,650,148 “Method of grafting genetically modified cells to treatdefects, disease or damage of the central nervous system”, and U.S. Pat.No. 5,936,078 “DNA and Protein for the Diagnosis and Treatment ofAlzheimer's Disease.”

The vast majority (˜95%) of AD cases are late-onset, occurring in theseventh or eighth decade. Late-onset AD is not associated with mutationsin APP, PS1 or PS2, yet exhibits neuropathological lesions and symptomsthat are similar to those found in early-onset AD. Since late-onset ADis the most common form, it will be referred to herein as AD, whileearly-onset AD will be referred to as such. The similar neuropathologyand outward symptoms of early-onset and late-onset AD have led to the“amyloid cascade hypothesis of AD” (Selkoe, 1994). This model holds thatboth early and late onset AD result from accumulation of toxic amyloiddeposits. The model speculates that in early onset cases, amyloidaccumulates rapidly, while in late onset, amyloid accumulates slowly.Much of the research on prevention and treatment of AD has focused oninhibition of amyloid accumulation. However, the amyloid cascadehypothesis remains controversial. Amyloid deposits may be a marker forthe disease and not the cause. Translation of Dr. Alzheimer's originalwork on the neuropathology of AD, relates that he did not favor the viewthat senile plaques were causative. He states “These changes are foundin the basal ganglia, the medulla, the cerebellum and the spinal cord,although there are no plaques at all in those sites or only isolatedones. So we have to conclude that the plaques are not the cause ofsenile dementia but only an accompanying feature of senile involution ofthe central nervous system.” The italics are his own (Davis andChisholm, 1999). Many years of research have not resolved this issue(for review of amyloid hypothesis see Selkoe, 1999, for counter argumentsee Neve et al., 1998). Since the present invention addresses thedecreased neuronal metabolism associated with AD, it does not rely onthe validity of the amyloid cascade hypothesis.

Several genetic risk factors have been proposed to contribute to thesusceptibility to late-onset AD. However, only allelic variation in thelipid transport molecule apolipoprotein E (apoE) has been reproduciblydefined as a genetic risk factor for late onset AD. ApoE functions as aligand in the process of receptor mediated internalization of lipid-richlipoproteins. These lipoprotein complexes contain phosopholipids,triglycerides, cholesterol and lipoproteins. Several well-characterizedallelic variations exist at the apoE locus, and are referred to asapoE2, E3 and E4. ApoE4 is associated with an increased risk of AD,while apoE2 and E3 are not. Increasing the dosage of the E4 alleleincreases the risk of AD, and lowers the age of onset. However, apoE4 isnot an invariant cause of AD. Some individuals, who are homozygous forthe E4 allele, do not show AD symptoms even into the ninth decade(Beffert et al., 1998).

A prediction of the observation that apoE4 is associated with AD is thatpopulations with a high prevalence of the E4 allele would also have ahigh incidence of AD. Yet, the opposite appears to be true.Geographically distinct populations have differing frequencies of apoEalleles. For example, the E4 variant is much more common in Africaversus the UK. In a study of black South Africans and Caucasians fromCambridge, England, the apoE4 allele was present in 48% of Black SouthAfricans compared to 20.8% of Caucasians (Loktionov et al, 1999). Infact, the E4 allele is widespread throughout Africa (Zekraoui et al,1997). Studies on AD are difficult to do in developing countries, butthe studies that have been done show a very low incidence of AD inAfrican communities, 1% versus 6% in US populations (Hall et al, 1998).Even more striking is that the normally robust association between ADand apoE4 is absent in African cases (Osuntokun et al, 1995). Thissuggests that something is different between native Africans, and UScitizens, who are largely of European descent. Perhaps the Africanpopulations have some other genetic factor that protects them from AD.This is unlikely, since the incidence of AD in a population ofAfrican-Americans from Indianapolis, Ind. USA (6.24%) was found to bemuch higher than an ethnically similar population in Ibadan, Nigeria(1.4%) (Hall et al, 1998). This suggests that the link between apoE4 andAD has some strong environmental component.

ApoE4 is the ancestral allele, it is most similar to the apoE found inchimpanzees and other primates, while the E2 and E3 alleles aroseexclusively in the human lineage, (Hanlon and Rubinsztein, 1995). Thechanges in apoE were probably brought about by a change in diet inancestral humans. The E2 and E3 alleles may have arisen in populationsas an adaptation to agriculture (Corbo and Scacchi, 1999).

The metabolism of apoE4 in human circulation is different from thenon-AD associated apoE3 allele (Gregg et al., 1986). The E4 allele isassociated with unusually high levels of circulating lipoproteins (Gregget al., 1986). In particular, the E4 allele results in decreased ratesof VLDL clearance, which leads to higher levels of VLDL and LDLparticles in the blood (Knouff, et al. 1999). VLDL and LDL particlescontain higher levels of triglycerides than HDL particles. The increasedlevels of circulating VLDL in individuals carrying apoE4 is due todecreased fatty acid utilization caused by preferential binding of apoE4to chylomicron and VLDL particles. Prior art has suggested that apoE4contributes to AD due to inefficient delivery of phospholipids toneurons (for review see Beffert et al., 1998). Yet, apoE4 also clearlycontributes to decreased triglyceride usage.

In the central nervous system (CNS), apoE plays a central role in thetransportation and redistribution of cholesterol and lipids. Theimportance of apoE in the brain is highlighted by the absence of otherkey plasma apolipoproteins such as apoA1 and apoB in the brain (Roheimet al., 1979). ApoE mRNA is found predominantly in astrocytes in theCNS. Astrocytes function as neuronal support cells and can efficientlyutilize fatty acids for energy. Since the brain lacks otherapolipoproteins, it is uniquely dependent on apoE for lipid transport.While prior art on apoE's role in AD has focused on phospholipidtransport, apoE also delivers free fatty acids in the form oftriglycerides to astrocytes. Fatty acids delivered by lipoproteins canbe converted to ketone bodies by astrocytes for use as an alternativeenergy source to glucose. An alternative to the neuronal remodelinghypothesis, is that the preferential binding of apoE4 to VLDL particlesprevents efficient astrocyte access to triglycerides. Decreased accessto triglycerides results in decreased availability of fatty acids anddecreased production of ketone bodies, and hence a decreased alternativeenergy source for cerebral neurons. This reduction in energy suppliesmay become critical when glucose metabolism in compromised.

Metabolism and Alzheimer's Disease.

At the time of this application, the cause of AD remains unknown, yet alarge body of evidence has made it clear that Alzheimer's Disease isassociated with decreased neuronal metabolism. In 1984, Blass and Zemcovproposed that AD results from a decreased metabolic rate insub-populations of cholinergic neurons. However, it has become clearthat AD is not restricted to cholinergic systems, but involves manytypes of transmitter systems, and several discrete brain regions.Positron-emission tomography has revealed poor glucose utilization inthe brains of AD patients, and this disturbed metabolism can be detectedwell before clinical signs of dementia occur (Reiman et al., 1996;Messier and Gagnon, 1996; Hoyer, 1998). Additionally, certainpopulations of cells, such as somatostatin cells of the cortex in ADbrain are smaller, and have reduced Golgi apparatus; both indicatingdecreased metabolic activity (for review see Swaab et al. 1998).Measurements of the cerebral metabolic rates in healthy versus ADpatients demonstrated a 20-40% reduction in glucose metabolism in ADpatients (Hoyer, 1992). Reduced glucose metabolism results in criticallylow levels of ATP in AD patients. Also, the severity of decreasedmetabolism was found to correlate with senile plaque density(Meier-Ruge, et al. 1994).

Additionally, molecular components of insulin signaling and glucoseutilization are impaired in AD patients. Glucose is transported acrossthe blood brain barrier and is used as a major fuel source in the adultbrain. Consistent with the high level of glucose utilization, the brainsof mammals are well supplied with receptors for insulin and IGF,especially in the areas of the cortex and hippocampus, which areimportant for learning and memory (Frolich et al., 1998). In patientsdiagnosed with AD, increased densities of insulin receptor were observedin many brain regions, yet the level of tyrosine kinase activity thatnormally is associated with the insulin receptor was decreased, bothrelative to age-matched controls (Frolich et al., 1998). The increaseddensity of receptors represents up-regulation of receptor levels tocompensate for decreased receptor activity. Activation of the insulinreceptor is known to stimulate phosphatidylinositol-3 kinase (PI3K).PI3K activity is reduced in AD patients (Jolles et al., 1992; Zubenko etal., 1999). Furthermore, the density of the major glucose transportersin the brain, GLUT1 and GLUT3 were found to be 50% of age matchedcontrols (Simpson and Davies, 1994). The disturbed glucose metabolism inAD has led to the suggestion that AD may be a form of insulin resistancein the brain, similar to type II diabetes (Hoyer, 1998). Inhibition ofinsulin receptor activity can be exogenously induced in the brains ofrats by intracerebroventricular injection of streptozotocin, a knowninhibitor of the insulin receptor. These animals develop progressivedefects in learning and memory (Lannert and Hoyer, 1998). While glucoseutilization is impaired in brains of AD patients, use of the ketonebodies, beta-hydroxybutyrate and acteoacetate is unaffected (Ogawa etal., 1996).

The cause of decreased neuronal metabolism in AD remains unknown. Yet,aging may exacerbate the decreased glucose metabolism in AD. Insulinstimulation of glucose uptake is impaired in the elderly, leading todecreased insulin action and increased insulin resistance (for reviewsee Finch and Cohen, 1997). For example, after a glucose load, meanplasma glucose is 10-30% higher in those over 65 than in youngersubjects. Hence, genetic risk factors for AD may result in slightlycompromised neuronal metabolism in the brain. These defects would onlybecome apparent later in life when glucose metabolism becomes impaired,and thereby contribute to the development of AD. Since the defects inglucose utilization are limited to the brain in AD, the liver is“unaware” of the state of the brain and does not mobilize fatty acids(see Brain Metabolism section below). Without ketone bodies to use as anenergy source, the neurons of the AD patient brain slowly and inexorablystarve to death.

Attempts to compensate for reduced cerebral metabolic rates in ADpatients has met with some success. Treatment of AD patients with highdoses of glucose and insulin increases cognitive scores (Craft et al.,1996). However, since insulin is a polypeptide and must be transportedacross the blood brain barrier, delivery to the brain is complicated.Therefore, insulin is administered systemically. A large dose of insulinin the blood stream can lead to hyperinsulinemia, which will causeirregularities in other tissues. Both of these shortcomings make thistype of therapy difficult and rife with complications. Accordingly,there remains a need for an agent that may increase the cerebralmetabolic rate and subsequently the cognitive abilities of a patientsuffering from Alzheimer's Disease.

Brain Metabolism.

The brain has a very high metabolic rate. For example, it uses 20percent of the total oxygen consumed in a resting state. Large amountsof ATP are required by neurons of the brain for general cellularfunctions, maintenance of an electric potential, synthesis ofneurotransmitters and synaptic remodeling. Current models propose thatunder normal physiologic conditions, neurons of the adult human braindepend solely on glucose for energy. Since neurons lack glycogen stores,the brain depends on a continuous supply of glucose from the blood forproper function. Neurons are very specialized and can only efficientlymetabolize a few substrates, such as glucose and ketone bodies. Thislimited metabolic ability makes brain neurons especially vulnerable tochanges in energy substrates. Hence, sudden interruption of glucosedelivery to the brain results in neuronal damage. Yet, if glucose levelsdrop gradually, such as during fasting, neurons will begin to metabolizeketone bodies instead of glucose and no neuronal damage will occur.

Neuronal support cells, glial cells, are much more metabolically diverseand can metabolize many substrates, in particular, glial cells are ableto utilize fatty acids for cellular respiration. Neurons of the braincannot efficiently oxidize fatty acids and hence rely on other cells,such as liver cells and astrocytes to oxidize fatty acids and produceketone bodies. Ketone bodies are produced from the incomplete oxidationof fatty acids and are used to distribute energy throughout the bodywhen glucose levels are low. In a normal Western diet, rich incarbohydrates, insulin levels are high and fatty acids are not utilizedfor fuel, hence blood ketone body levels are very low, and fat is storedand not used. Current models propose that only during special states,such as neonatal development and periods of starvation, will the brainutilize ketone bodies for fuel. The partial oxidation of fatty acidsgives rise to D-beta-hydroxybutyrate (D-3-β-hydroxybutyrate) andacetoacetate, which together with acetone are collectively called ketonebodies. Neonatal mammals are dependent upon milk for development. Themajor carbon source in milk is fat (carbohydrates make up less then 12%of the caloric content of milk). The fatty acids in milk are oxidized togive rise to ketone bodies, which then diffuse into the blood to providean energy source for development. Numerous studies have shown that thepreferred substrates for respiration in the developing mammalianneonatal brain are ketone bodies. Consistent with this observation isthe biochemical finding that astrocytes, oligodendrocytes and neuronsall have capacity for efficient ketone body metabolism (for review seeEdmond, 1992). Yet only astrocytes are capable of efficient oxidation offatty acids to ketone bodies.

The body normally produces small amounts of ketone bodies. However,because they are rapidly utilized, the concentration of ketone bodies inthe blood is very low. Blood ketone body concentrations rise on a lowcarbohydrate diet, during periods of fasting, and in diabetics. In a lowcarbohydrate diet, blood glucose levels are low, and pancreatic insulinsecretion is not stimulated. This triggers the oxidation of fatty acidsfor use as a fuel source when glucose is limiting. Similarly, duringfasting or starvation, liver glycogen stores are quickly depleted, andfat is mobilized in the form of ketone bodies. Since both a lowcarbohydrate diet and fasting do not result in a rapid drop of bloodglucose levels, the body has time to increase blood ketone levels. Therise in blood ketone bodies provides the brain with an alternative fuelsource, and no cellular damage occurs. Since the brain has such highenergy demands, the liver oxidizes large amounts of fatty acids untilthe body becomes literally saturated with ketone bodies. Therefore, whenan insufficient source of ketone bodies is coupled with poor glucoseutilization severe damage to neurons results. Since glial cells are ableto utilize a large variety of substrates they are less susceptible todefects in glucose metabolism than are neurons. This is consistent withthe observation that glial cells do not degenerate and die in AD(Mattson, 1998).

As discussed in the Metabolism and Alzheimer's Disease section, in AD,neurons of the brain are unable to utilize glucose and begin to starveto death. Since the defects are limited to the brain and peripheralglucose metabolism is normal, the body does not increase production ofketone bodies, therefore neurons of the brain slowly starve to death.Accordingly, there remains a need for an energy source for brain cellsthat exhibit compromised glucose metabolism. Compromised glucosemetabolism is a hallmark of AD; hence administration of such an agentwill prove beneficial to those suffering from AD.

Huntington's Disease

Huntington's Disease (HD) is a familial neurodegenerative disorder thatafflicts 1/10,000 individuals. It is inherited in an autosomal dominantmanner and is characterized by choreiform movements, dementia, andcognitive decline. The disease is produced by genes containing avariably increased (expanded) CAG repeat within the coding region. Thesize range of the repeats is similar in all diseases; unaffectedindividuals have fewer than 30 CAG repeats, whereas affected patientsusually have more than 40 repeats. The disorder usually has a mid-lifeonset, between the ages of 30 to 50 years, but may in some cases beginvery early or much later in life. The size of the inherited CAG repeatcorrelates with the severity and age of disease onset. The CAG tripletrepeat produces a polyglutamine domain in the expressed proteins. Thesymptoms are progressive and death typically ensues 10 to 20 years afteronset, most often as the result of secondary complications of themovement disorder.

The mutant gene produces huntington protein, whose function is unknown.The polyglutamine regions of Huntington interact withglyceraldehyde-3-phosphate dehydrogenase (GAPDH), a key glycolyticenzyme. While normal glutamine can bind with GAPDH and cause no harm tothe enzyme, binding of mutant Huntington inhibits the enzyme. It isbelieved that the lack of energy being supplied to the brain cells, dueto the interference of the Huntington protein with GAPDH, in part,causes neuron damage in the basal ganglia and the cerebral cortex.Mitochondrial dysfunction has also been implicated HD.

At least four other diseases are caused by the expanded CAG repeat, andthus also may implicate defective glucose metabolism. These includespinobulbar muscular atrophy, dentatorubral-pallidoluysian atrophy(DRPLA), spino-cerebellar ataxia type 1, and spino-cerebellar ataxiatype 3.

Parkinson's Disease

Parkinson's Disease (PD) is widely considered to be the result ofdegradation of the pre-synaptic dopaminergic neurons in the brain, witha subsequent decrease in the amount of the neurotransmitter dopaminethat is being released. Inadequate dopamine release, therefore, leads tothe onset of voluntary muscle control disturbances symptomatic of PD.

The motor dysfunction symptoms of PD have been treated in the past usingdopamine receptor agonists, monoamine oxidase binding inhibitors,tricyclic antidepressants, anticholinergics, and histamineH1-antagonists. Unfortunately, the main pathologic event, degenerationof the cells in substantia nigra, is not helped by such treatments. Thedisease continues to progress and, frequently after a certain length oftime, dopamine replacement treatment will lose its effectiveness. Inaddition to motor dysfunction, however, PD is also characterized byneuropsychiatric disorders or symptoms. These includeapathy-amotivation, depression, and dementia. PD patients with dementiahave been reported to respond less well to standard L-dopa therapy.Moreover, these treatments have little or no benefit with respect to theneuropsychiatric symptoms. Impaired neuronal metabolism is believed tobe a contributing factor to PD.

Epilepsy

Epilepsy, sometimes called a seizure disorder, is a chronic medicalcondition produced by temporary changes in the electrical function ofthe brain, causing seizures which affect awareness, movement, orsensation. There has been long experience with ketogenic diets, whichmimic starvation, in children treated for epilepsy. The diet is amedical therapy and should be used under the careful supervision of aphysician and/or dietician. The diet carefully controls caloric inputand requires that the child eat only what has been included in thecalculations to provide 90% of the day's calories as fats. However, suchdiets are generally unsuitable for use in adults due to: (1) adverseeffects on the circulatory system from incorporation of long chaintriglycerides as the primary fat in these diets into cholesterol and theeffects of hyperlipidemia; (2) poor patient compliance due to theunappealing nature of the low carbohydrate diet.

Medium Chain Triglycerides (MCT)

The metabolism of MCT differs from the more common long chaintriglycerides (LCT) due to the physical properties of MCT and theircorresponding medium chain fatty acids (MCFA). Due to the short chainlength of MCFA, they have lower melting temperatures, for example themelting point of MCFA (C8:0) is 16.7° C., compared with 61.1° C. for theLCFA (C16:0). Hence, MCT and MCFA are liquid at room temperature. MCTare highly ionized at physiological pH, thus they have much greatersolubility in aqueous solutions than LCT. The enhanced solubility andsmall size of MCT also increases the rate at which fine emulsionparticles are formed. These small emulsion particles create increasedsurface area for action by gastrointestinal lipases. Additionally,medium chain 2-monoglycerides isomerize more rapidly than those of longchain length, allowing for more rapid hydrolysis. Some lipases in thepre-duodenum preferentially hydrolyze MCT to MCFA, which are then partlyabsorbed directly by stomach mucosa (Hamosh, 1990). Those MCFA which arenot absorbed in the stomach, are absorbed directly into the portal veinand not packaged into lipoproteins. LCFA are packaged in chylomicronsand transported via the lymph system, while MCFA are transported via theblood. Since blood transports much more rapidly than lymph, the liver isquickly perfused with MCFA.

In the liver the major metabolic fate of MCFA is oxidation. The fate ofLCFA in the liver is dependent on the metabolic state of the organism.LCFA are transported into the mitochondria for oxidation using carnitinepalmitoyltransferase I. When conditions favor fat storage, malonyl-CoAis produced as an intermediate in lipogenesis. Malonyl-CoAallosterically inhibits carnitine palmitoyltransferase I, and therebyinhibits LCFA transport into the mitochondria. This feedback mechanismprevents futile cycles of lipolysis and lipogenesis. MCFA are, to largeextent, immune to the regulations that control the oxidation of LCFA.MCFA enter the mitochondria largely without the use of carnitinepalmitoyltransferase I, therefore MCFA by-pass this regulatory step andare oxidized regardless of the metabolic state of the organism.Importantly, since MCFA enter the liver rapidly and are quicklyoxidized, large amounts of ketone bodies are readily produced from MCFA.

Numerous patents relate to use of MCT. None of these patents relate tothe specific use of MCT for treatment and prevention of Alzheimer'sDisease or other neurodegenerative diseases. Patents such as U.S. Pat.No. 4,528,197 “Controlled triglyceride nutrition for hypercatabolicmammals” and U.S. Pat. No. 4,847,296 “Triglyceride preparations for theprevention of catabolism” relate to the use of MCT to prevent body-widecatabolism that occurs in burns and other serious injuries. Each patentdescribed herein is incorporated by reference herein in its entirety.

SUMMARY OF THE INVENTION

The present invention provides a method of treating or preventingdementia of Alzheimer's type, or other loss of cognitive function causedby reduced neuronal metabolism, comprising administering an effectiveamount of medium chain triglycerides to a patient in need thereof.Administration may be oral or intravenous.

The medium chain triglycerides may be emulsified, and may becoadministered with L-carnitine or a derivative of L-carnitine.

The present invention also provides a method of treating or preventingdementia of Alzheimer's type, or other loss of cognitive function causedby reduced neuronal metabolism, comprising administering an effectiveamount of free fatty acids derived from medium chain triglycerides to apatient in need thereof.

The present invention also provides a method of treating or preventingdementia of Alzheimer's type, or other loss of cognitive function causedby reduced neuronal metabolism, comprising administering an effectiveamount of a medium chain triglyceride prodrug to a patient in needthereof.

The present invention also provides a method of treating or preventingdementia of Alzheimer's type, or other loss of cognitive function causedby reduced neuronal metabolism, comprising administering an effectiveamount of a therapeutic agent which induces utilization of fatty acidsand development of ketosis to a patient in need thereof.

The present invention further provides therapeutic agents for thetreatment or prevention of dementia of Alzheimer's type, or other lossof cognitive function caused by reduced neuronal metabolism. The presentinvention also provides pharmaceutical compositions. In one instance thepharmaceutical composition comprises a medium chain triglyceride and asugar, including monosaccharides, disaccharides, polysaccharides, andmixtures thereof.

The present invention also provides a pharmaceutical compositioncomprising a medium chain triglyceride and a TCA cycle intermediate or ametabolic precursor of a TCA intermediate.

The present invention also provides a pharmaceutical compositioncomprising a medium chain triglyceride and a ketone body or metabolicprecursor of a ketone body, including β-hydroxybutyrate, acteoacetate,metabolic precursors of β-hydroxybutyrate or acteoacetate, aphysiologically acceptable salt or ester of a polymer or oligomers, andmixtures thereof.

The present invention also provides a pharmaceutical compositioncomprising a medium chain triglyceride and a metabolic adjuvant, such asa vitamin, a mineral, an antioxidant, an energy-enhancing compound, andmixtures thereof, Coenzyme CoQ-10, creatine, L-carnitine,n-acetyl-carnitine, L-carnitine derivatives, and mixtures thereof.

The present invention also provides therapeutic agents which arederivatives of MCT, and can include ketone body precursors and essentialfatty acids esterified to a the glycerol backbone.

The present invention further provides pharmaceutical compositionscomprising a medium chain triglyceride and a therapeutic agent selectedfrom the group consisting of acetylcholinesterase inhibitors,acetylcholine synthesis modulators, acetylcholine storage modulators,acetylcholine release modulators, anti-inflammatory agents, estrogen orestrogen derivatives, insulin sensitizing agents, β-amyloid plaqueremoval agents (including vaccines), inhibitors of β-amyloid plaqueformation, γ-secretase modulators, pyruvate dehydrogenase complexmodulators, α-ketoglutarate dehydrogenase complex modulators,neurotrophic growth factors (e.g., BDNF), ceramides or ceramide analogs,and/or NMDA glutamate receptor antagonists.

The present invention further provides a pharmaceutical compositioncomprising a medium-chain triglyceride and at least one therapeuticagent which induces utilization of fatty acids, including a PPAR-gammaagonist such as aspirin, ibuprofen, ketoprofen, and naproxen, andthiazolidinedione drugs, a statin drug such as Liptor or Zocor, fibratedrugs such as Bezafibrate, ciprofibrate, fenofibrate or Gemfibrozil,caffeine, and ephedra.

The present invention also provides a method of individualizing atreatment for Alzheimer's Disease, comprising determining a patient'sapolipoprotein E genotype and providing a pharmaceutical compositioncomprising medium chain triglycerides which provides an ketone bodylevel effective for treatment of Alzheimer's Disease for said genotypeto individualize the treatment for Alzheimer's Disease.

The present invention further provides a method of elevating ketone bodylevels comprising administering a medium chain triglyceride to a patientin need thereof,

The present invention also provides methods of increasing cognitiveability in a patient suffering from Alzheimer's Disease, comprisingadministering medium chain triglycerides to a patient in need thereof orcomprising increasing ketone body levels in the patient.

The present invention also provides a method of treating reducedneuronal metabolism comprising administering a therapeutic agent whichinduces utilization of fatty acids, including a PPAR-gamma agonist, astatin drug, and a fibrate drug.

The present invention provides a method of treating or preventingdementia of Alzheimer's type, or other loss of cognitive function causedby reduced neuronal metabolism, comprising administering an agentcapable of increasing blood serum ketone body levels to a patient inneed thereof.

The present invention provides a pharmaceutical composition comprisingβ-hydroxybutyrate, acteoacetate, metabolic precursors ofβ-hydroxybutyrate or acteoacetate, mixtures of the foregoing, and oneselected from the group consisting of a PPAR-gamma agonist, a statindrug, and a fibrate drug.

The present invention also provides a method of treating or preventingdementia of Alzheimer's type, or other loss of cognitive function causedby reduced neuronal metabolism, comprising administering an effectiveamount of a pharmaceutical composition of claim 51 to a patient in needthereof.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows a schematic of the TCA cycle as it occurs in the cell.

FIG. 2 shows the results of treatment on cognitive performance forapoE4+ and apoE4− patients.

DETAILED DESCRIPTION OF THE INVENTION

It is the novel insight of this invention that medium chaintriglycerides (MCT) and their associated fatty acids are useful as atreatment and preventative measure for AD patients. As used herein,“patient” refers to any mammal, including humans, that may benefit fromtreatment of disease and conditions resulting from reduced neuronalmetabolism. As used herein, reduced neuronal metabolism refers to allpossible mechanisms that could lead to a reduction in neuronalmetabolism. Such mechanisms include, but are not limited tomitochondrial dysfunction, free radical attack, defective glucosetransport or glycolysis, imbalance in membrane ionic potential,dysfunction in calcium flux, and the like. MCT are composed of fattyacids with chain lengths of between 5-12 carbons. A diet rich in MCTresults in high blood ketone levels. High blood ketone levels willprovide an energy source for brain cells that have compromised glucosemetabolism via the rapid oxidation of MCFA to ketone bodies.

The background of this invention supports the present invention in thefollowing ways. (1) Neurons of the brain can use both glucose and ketonebodies for respiration. (2) The neurons of Alzheimer's Disease patientshave well documented defects in glucose metabolism. (3) Known geneticrisk factors for Alzheimer's Disease are associated with lipid andcholesterol transport, suggesting defects in triglyceride usage that mayunderlie susceptibility to Alzheimer's Disease. (4) ingestion of MCTwill lead to increased levels of blood ketone bodies and thereby provideenergy to starving brain neurons. Hence, supplementation of Alzheimer'sDisease patients with MCT will restore neuronal metabolism.Additionally, defects in neuronal metabolism in Huntington's Disease,Parkinson's Disease, and epilepsy and other related neurodegenerativediseases such as Wernicke-Korsakoff Disease and possibly schizophreniawill be benefited by high blood ketone levels, derived from MCT thatprovide an energy source for brain cells. As used herein, “high bloodketone levels” refers to levels of at least about 0.1 mM. Morepreferably, high blood ketone levels refers to levels in the range of0.1 to 50 mM, more preferably in the range of 0.2-20 mM, more preferablyin the range of 0.3-5 mM, and more preferably in the range of 0.5-2 mM.

It is also the novel insight of this invention that a combination ofMCTs and therapeutic agents that increase the utilization of fatty acidsby any mechanism are useful as a treatment and preventative measure forAD patients.

The present invention provides a method of treating or preventingdementia of Alzheimer's type, or other loss of cognitive function causedby reduced neuronal metabolism, comprising administering an effectiveamount of medium chain triglycerides to a patient in need thereof.Generally, an effective amount is an amount effective to either (1)reduce the symptoms of the disease sought to be treated or (2) induce apharmacological change relevant to treating the disease sought to betreated. For Alzheimer's Disease, an effective amount includes an amounteffective to: increase cognitive scores; slow the progression ofdementia; or increase the life expectancy of the affected patient. Asused herein, medium chain triglycerides of this invention arerepresented by the following formula:

wherein R₁ is independently selected from the group consisting of afatty acid residue esterified to a glycerol backbone having 5-12 carbonsin the carbon backbone (C₅ to C₁₂ fatty acids), a saturated fatty acidresidue esterified to a glycerol backbone having 5-12 carbons in thecarbon backbone (C₅ to C₁₂ fatty acids), an unsaturated fatty acidresidue esterified to a glycerol backbone having 5-12 carbons in thecarbon backbone (C₅ to C₁₂ fatty acids), and derivatives of any of theforegoing. The structured lipids of this invention may be prepared byany process known in the art, such as direct esterification,rearrangement, fractionation, transesterification, or the like. Forexample the lipids may be prepared by the rearrangement of a vegetableoil such as coconut oil.

In a preferred embodiment, the method comprises the use of MCTs whereinR₁ is a fatty acid containing a six-carbon backbone (tri-C6:0). Tri-C6:0MCT are absorbed very rapidly by the gastrointestinal track in a numberof animal model systems (Odle 1997). The high rate of absorption resultsin rapid perfusion of the liver, and a potent ketogenic response. Inanother preferred embodiment, the method comprises the use of MCTswherein R₁ is a fatty acid containing a eight-carbon backbone(tri-C8:0). Additionally, utilization of tri-C6:0 MCT and tri-C8:0 MCTcan be increased by emulsification. Emulsification of lipids increasesthe surface area for action by lipases, resulting in more rapidhydrolysis. Methods for emulsification of these triglycerides are wellknown to those skilled in the art.

In Example 3, the inventor demonstrates the efficacy of tri-C8:0 mediumchain triglycerides (MCT) in the treatment of AD. In this example theinventor reveals several key aspects of the invention. First, MCT induceelevated ketone body levels in the elderly (mean age=74.7 years).Second, MCT induce different ketone body levels in different subjectsbased on their apolipoprotein E genotype. Third, MCT treatments resultin improved performance on established Alzheimer Disease cognitivemeasures (ADAS-cog). Fourth, improved performance on ADAS-cog test wasinfluenced by the subject's apolipoprotein E genotype. Fifth, higherketone body levels were associated with greater improvement in a secondmeasure of cognitive performance (the paragraph recall test) with MCTtreatment.

In another preferred embodiment, the invention provides a method oftreating or preventing dementia of Alzheimer's type, or other loss ofcognitive function caused by reduced neuronal metabolism, comprisingadministering an effective amount of free fatty acids, which may bederived from medium chain triglycerides, to a patient in need thereof.Because MCT are metabolized to produce medium chain fatty acids, whichare oxidized, the administration of free fatty acids and/or ketonebodies have the same effect as the administration of MCT themselves.

In another preferred embodiment, the invention comprises thecoadministration of emulsified tri-C6:0 MCT and L-carnitine or aderivative of L-carnitine. Slight increases in MCFA oxidation have beennoted when MCT are combined with L-carnitine (Odle, 1997). Thus in thepresent invention emulsified MCT are combined with L-carnitine at dosesrequired to increase the utilization of said MCT. The dosage ofL-carnitine and MCT will vary according to the condition of the host,method of delivery, and other factors known to those skilled in the art,and will be of sufficient quantity to raise blood ketone levels to adegree required to treat and prevent Alzheimer's Disease. Derivatives ofL-carnitine which may be used in the present invention include but arenot limited to decanoylcarnitine, hexanoylcarnitine, caproylcarnitine,lauroylcarnitine, octanoylcarnitine, stearoylcarnitine,myristoylcarnitine, acetyl-L-carnitine, O-Acetyl-L-carnitine, andpalmitoyl-L-carnitine.

Therapeutically effective amounts of the therapeutic agents can be anyamount or dose sufficient to bring about the desired anti-dementiaeffect and depend, in part, on the severity and stage of the condition,the size and condition of the patient, as well as other factors readilyknown to those skilled in the art. The dosages can be given as a singledose, or as several doses, for example, divided over the course ofseveral weeks.

In one embodiment, the MCT or fatty acids are administered orally. Inanother embodiment, the MCT are administered intravenously. Oraladministration of MCT and preparations of intravenous MCT solutions arewell known to those skilled in the art.

Oral and intravenous administration of MCT or fatty acids result inhyperketonemia. Hyperketonemia results in ketone bodies being utilizedfor energy in the brain even in the presence of glucose. Additionally,hyperketonemia results in a substantial (39%) increase in cerebral bloodflow (Hasselbalch et al. 1996). Hyperketonemia has been reported toreduce cognitive dysfunction associated with systemic hypoglycemia innormal humans (Veneman et al. 1994). Please note that systemichypoglycemia is distinct from the local defects in glucose metabolismthat occur in AD.

In another embodiment, the invention provides the subject compounds inthe form of one or more prodrugs, which can be metabolically convertedto the subject compounds by the recipient host. As used herein, aprodrug is a compound that exhibits pharmacological activity afterundergoing a chemical transformation in the body. The said prodrugs willbe administered in a dosage required to increase blood ketone bodies toa level required to treat and prevent the occurrence of Alzheimer'sDisease. A wide variety of prodrug formulations are known in the art.For example, prodrug bonds may be hydrolyzable, such as esters oranhydrides, or enzymatically biodegradable, such as amides.

This invention also provides a therapeutic agent for the treatment orprevention of dementia of Alzheimer's type, or other loss of cognitivefunction caused by reduced neuronal metabolism, comprising medium chaintriglycerides. In a preferred embodiment, the therapeutic agent isprovided in administratively convenient formulations of the compositionsincluding dosage units incorporated into a variety of containers.Dosages of the MCT are preferably administered in an effective amount,in order to produce ketone body concentrations sufficient to increasethe cognitive ability of patients afflicted with AD or other states ofreduced neuronal metabolism. For example, for the ketone body,D-beta-hydroxybutyrate, blood levels are raised to about 0.1-50 mM0.1-50 (measured by urinary excretion in the range of about 5 mg/dL toabout 160 mg/dL), more preferably raised to about 0.2-20 mM, morepreferably raised to about 0.3-5 mM, more preferably raised to about0.5-2 mM, although variations will necessarily occur depending on theformulation and host, for example. Effective amount dosages of other MCTwill be apparent to those skilled in the art. In one embodiment, an MCTdose will be in the range of 0.05 g/kg/day to 10 g/kg/day of MCT. Morepreferably, the dose will be in the range of 0.25 g/kg/day to 5 g/kg/dayof MCT. More preferably, the dose will be in the range of 0.5 g/kg/dayto 2 g/kg/day of MCT. Convenient unit dosage containers and/orformulations include tablets, capsules, lozenges, troches, hard candies,nutritional bars, nutritional drinks, metered sprays, creams, andsuppositories, among others. The compositions may be combined with apharmaceutically acceptable excipient such as gelatin, an oil, and/orother pharmaceutically active agent(s). For example, the compositionsmay be advantageously combined and/or used in combination with othertherapeutic or prophylactic agents, different from the subjectcompounds.

In many instances, administration in conjunction with the subjectcompositions enhances the efficacy of such agents. For example, thecompounds may be advantageously used in conjunction with antioxidants,compounds that enhance the efficiency of glucose utilization, andmixtures thereof, (see e.g. Goodman et al. 1996).

In a preferred embodiment the human subject is intravenously infusedwith MCT, MCFA (medium chain fatty acids) and/or ketone bodies directly,to a level required to treat and prevent the occurrence of Alzheimer'sDisease. Preparation of intravenous lipid, and ketone body solutions iswell known to those skilled in the art.

In a preferred embodiment, the invention provides a formulationcomprising a mixture of MCT and carnitine to provide elevated bloodketone levels. The nature of such formulations will depend on theduration and route of administration. Such formulations will be in therange of 0.05 g/kg/day to 10 g/kg/day of MCT and 0.05 mg/kg/day to 10mg/kg/day of carnitine or its derivatives. In one embodiment, an MCTdose will be in the range of 0.05 g/kg/day to 10 g/kg/day of MCT. Morepreferably, the dose will be in the range of 0.25 g/kg/day to 5 g/kg/dayof MCT. More preferably, the dose will be in the range of 0.5 g/kg/dayto 2 g/kg/day of MCT.

In some embodiments, a carnitine or carnitine derivative dose will be inthe range of 0.05 g/kg/day to 10 g/kg/day. More preferably, thecarnitine or carnitine derivative dose will be in the range of 0.1g/kg/day to 5 g/kg/day. More preferably, the carnitine or carnitinederivative dose will be in the range of 0.5 g/kg/day to 1 g/kg/day.Variations will necessarily occur depending on the formulation and/orhost, for example.

A particularly preferred formulation comprises a range of 1-500 g ofemulsified MCT combined with 1-2000 mg of carnitine. An even morepreferred formulation comprises 50 g MCT (95% triC8:0) emulsified with50 g of mono- and di-glycerides combined with 500 mg of L-carnitine.Such a formulation is well tolerated and induces hyperketonemia for 3-4hours in healthy human subjects.

In another embodiment, the invention provides the recipient with atherapeutic agent which enhances endogenous fatty acid metabolism by therecipient. The said therapeutic agent will be administered in a dosagerequired to increase blood ketone bodies to a level required to treatand prevent the occurrence of Alzheimer's Disease. Ketone bodies areproduced continuously by oxidation of fatty acids in tissues that arecapable of such oxidation. The major organ for fatty acid oxidation isthe liver. Under normal physiological conditions ketone bodies arerapidly utilized and cleared from the blood. Under some conditions, suchas starvation or low carbohydrate diet, ketone bodies are produced inexcess and accumulate in the blood stream. Compounds that mimic theeffect of increasing oxidation of fatty acids will raise ketone bodyconcentration to a level to provide an alternative energy source forneuronal cells with compromised metabolism. Since the efficacy of suchcompounds derives from their ability to increase fatty acid utilizationand raise blood ketone body concentration they are dependent on theembodiments of the present invention.

Compounds that mimic the effect of increasing oxidation of fatty acidsand will raise ketone body concentration include but are not limited tothe ketone bodies, D-β-hydroxybutyrate and aceotoacetate, and metabolicprecursors of these. The term metabolic precursor, as used herein,refers to compounds that comprise 1,3 butane diol, acetoacetyl orD-β-hydroxybutyrate moieties such as acetoacetyl-1-1,3-butane diol,acetoacetyl D-β-hydroxybutyate, and acetoacetylglycerol. Esters of anysuch compounds with monohydric, dihydric or trihydric alcohols is alsoenvisaged. Metabolic precursors also include polyesters ofD-β-hydroxybutyrate, and acetoaoacetate esters of D-β-hydroxybutyrate.Polyesters of D-β-hydroxybutyrate include oligomers of this polymerdesigned to be readily digestible and/or metabolized by humans oranimals. These preferably are of 2 to 100 repeats long, typically 2 to20 repeats long, and most conveniently from 3 to 10 repeats long.Examples of poly D-β-hydroxybutyrate or terminally oxidizedpoly-D-β-hydroxybutyrate esters useable as ketone body precursors aregiven below:

In each case n is selected such that the polymer or oligomer is readilymetabolized on administration to a human or animal body to provideelevated ketone body levels in blood. Preferred values of n are integersof 0 to 1,000, more preferably 0 to 200, still more preferably 1 to 50,most preferably 1 to 20, particularly conveniently being from 3 to 5. Ineach case m is an integer of 1 or more, a complex thereof with one ormore cations or a salt thereof for use in therapy or nutrition. Examplesof cations and typical physiological salts are described herein, andadditionally include sodium, potassium, magnesium, calcium, eachbalanced by a physiological counter-ion forming a salt complex,L-lysine, L-arginine, methyl glucamine, and others known to thoseskilled in the art. The preparation and use of such metabolic precursorsis detailed in Veech, WO 98/41201, and Veech, WO 00/15216, each of whichis incorporated by reference herein in its entirety.

The present invention provides a compound of the formula:

wherein R₂ is independently selected from the group consisting of R₁, anessential fatty acid esterified to a glycerol backbone,f3-hydroxybutyrate esterified to a glycerol backbone, acetoacetateesterified to the glycerol backbone, compound 1 esterified to a glycerolbackbone, compound 2 esterified to a glycerol backbone, and compound 3esterified to a glycerol backbone, with the proviso that at least one ofR₂ is R₁. This compound will provide increased levels of ketone bodiesdue to the MCT character of the molecule where R₂ is a ketone bodyprecursor of the molecule. Additionally, where R₂ is an essential fattyacid, namely, linoleic or arachidonic acids, the compound has theadditional advantage of providing the essential fatty acid.

Accordingly, the present invention also provides a method of treating orpreventing dementia of Alzheimer's type, or other loss of cognitivefunction caused by reduced neuronal metabolism, comprising administeringan effective amount of the foregoing compound to a patient in needthereof.

In another embodiment, the invention provides a therapeutic compound ormixture of compounds, the composition and dosage of which is influencedby the patients' genotype, in particular the alleles of apoliproproteinE gene. In Example 3 the inventor discloses that non-E4 carriersperformed better than those with the E4 allele when elevated ketone bodylevels were induced with MCT. Also, those with the E4 allele had higherfasting ketone body levels and the levels continued to rise at the twohour time interval. Therefore, E4 carriers may require higher ketonelevels or agents that increase the ability to use the ketone bodies thatare present. Accordingly, a preferred embodiment consists of a dose ofMCT combined with agents that increase the utilization of fats, MCT orketone bodies. Examples of agents that increase utilization of fattyacids may be selected from a group comprising of, but not limited to,non-steroidal anti-inflammatory agents (NSAIDs), statin drugs (such asLipitor® and Zocor®) and fibrates. Examples of NSAIDs include: aspirin,ibuprofen (Advil, Nuprin, and others), ketoprofen (Orudis KT, Actron),and naproxen (Aleve).

NSAIDs function, in part, as PPAR-gamma agonists. Increasing PPAR-gammaactivity increases the expression of genes associated with fatty acidmetabolism such as FATP (for review see (Gelman, Fruchart et al. 1999)).Accordingly, a combination of MCT and PPAR-gamma agonists will provebeneficial to individuals with decreased neuronal metabolism. In apreferred embodiment the PPAR-gamma agonist is an NSAID.

Statins are a class of drugs with pleiotropic effects, the bestcharacterized being inhibition of the enzyme 3-hydroxy-3-methylglutarylCoA reductase, a key rate step in cholesterol synthesis. Statins alsohave other physiologic affects such as vasodilatory, anti-thrombotic,antioxidant, anti-proliferative, anti-inflammatory and plaquestabilizing properties. Additionally, statins cause a reduction incirculating triglyceride rich lipoproteins by increasing the levels oflipoprotein lipase while also decreasing apolipoprotein C-III (aninhibitor of lipoprotein lipase) (Schoonjans, Peinado-Onsurbe et al.1999). Accordingly, administration of statins results in increased fattyacid usage, which can act synergistically with MCT administration. Thisshould prove especially beneficial to ApoE4 carriers. One embodiment ofthis invention would be combination therapy consisting of statins andMCT.

Fibrates, such as Bezafibrate, ciprofibrate, fenofibrate andGemfibrozil, are a class of lipid lowering drugs. They act as PPAR-alphaagonists and similar to statins they increase lipoprotein lipase, apoAIand apoAII transcription and reduce levels of apoCIII (Staels,Dallongeville et al. 1998). As such they have a major impact on levelsof triglyceride rich lipoproteins in the plasma, presumably byincreasing the use of fatty acids by peripheral tissues. Accordingly,the present invention discloses that fibrates alone or in combinationwith MCT would prove beneficial to patients with reduced neuronalmetabolism such as those with Alzheimer's Disease.

Caffeine and ephedra alkaloids are commonly used in over the counterdietary supplements. Ephedra alkaloids are commonly derived from plantsources such as ma-huang (Ephedra sinica). The combination of caffeineand ephedra stimulate the use of fat. Ephedra alkaloids are similar instructure to adrenaline and activate beta-adenergic receptors on cellsurfaces. These adenergic receptors signal through cyclic AMP (cAMP) toincrease the use of fatty acids. cAMP is normally degraded byphosphodiesterase activity. One of the functions of caffeine is toinhibit phosphodiesterase activity and thereby increase cAMP mediatedsignaling. Therefore caffeine potentiates the activity of the ephedraalkaloids. Accordingly, the present invention discloses that ephedraalkaloids alone can provide a treatment or prevention for conditions ofreduced neuronal metabolism. Additionally, it is disclosed that ephedraalkaloids in combination with caffeine can provide a treatment orprevention for conditions of reduced neuronal metabolism. Accordingly,it is disclosed that a combination of MCT with ephedra, or MCT withcaffeine, or MCT, ephedra alkaloids and caffeine together can provide atreatment or prevention for conditions of reduced neuronal metabolism.

Ketone bodies are used by neurons as a source of Acetyl-CoA. Acetyl-CoAis combined with oxaloacetate to form citrate in the Krebs' cycle, orcitric acid cycle (TCA cycle) (see FIG. 1). It is important for neuronsto have a source of Acetyl-CoA as well as TCA cycle intermediates tomaintain efficient energy metabolism. Yet, neurons lose TCA cycleintermediates to synthesis reactions, such as the formation ofglutamate. Neurons also lack pyruvate carboxylase and malic enzyme sothey cannot replenish TCA cycle intermediates from pyruvate (Hertz, Yuet al. 2000). Accordingly, the present invention discloses that acombination of ketone bodies with a source of TCA cycle intermediateswill be beneficial to conditions of reduced neuronal metabolism. TCAcycle intermediates are selected from a group consisting of citric acid,aconitic acid, isocitric acid, α-ketoglutaric acid, succinic acid,fumaric acid, malic acid, oxaloacetic acid, and mixtures thereof. Oneembodiment of the invention is a combination of TCA cycle intermediateswith MCT in a formulation to increase efficiency of the TCA.

Another source of TCA cycle intermediates are compounds that areconverted to TCA cycle intermediates within the body (TCA intermediateprecursors). Examples of such compounds are 2-keto-4-hydroxypropanol,2,4-dihydroxybutanol, 2-keto-4-hydroxybutanol, 2,4-dihydroxybutyricacid, 2-keto-4-hydroxybutyric acid, aspartates as well as mono- anddi-alkyl oxaloacetates, pyruvate and glucose-6-phosphate. Accordingly,the present invention discloses that a combination of TCA intermediateprecursors with ketone bodies will be beneficial for the treatment andprevention of diseases resulting from reduced metabolism. Also, thepresent invention discloses that MCT combined with TCA intermediateprecursors will be beneficial for the treatment and prevention ofdiseases resulting from reduced metabolism.

The present invention further discloses that additional sources of TCAcycle intermediates and Acetyl-CoA can be advantageously combined withketone body therapy. Sources of TCA cycle intermediates and Acetyl-CoAinclude mono- and di saccharides as well as triglycerides of variouschain lengths and structures.

Further benefit can be derived from formulation of a pharmaceuticalcomposition that includes metabolic adjuvants. Metabolic adjuvantsinclude vitamins, minerals, antioxidants and other related compounds.Such compounds may be chosen from a list that includes but is notlimited to; ascorbic acid, biotin, calcitriol, cobalamin, folic acid,niacin, pantothenic acid, pyridoxine, retinol, retinal (retinaldehyde),retinoic acid, riboflavin, thiamin, α-tocopherol, phytylmenaquinone,multiprenylmenaquinone, calcium, magnesium, sodium, aluminum, zinc,potassium, chromium, vanadium, selenium, phosphorous, manganese, iron,fluorine, copper, cobalt, molybdenum, iodine. Accordingly a combinationof ingredients chosen from: metabolic adjuvants, compounds that increaseketone body levels, and TCA cycle intermediates, will prove beneficialfor treatment and prevention of diseases associated with decreasedmetabolism, including Alzheimer's Disease, Parkinson's Disease,Huntington's Disease, and epilepsy.

With regard to epilepsy, the prior art provides descriptions ofketogenic diets in which fat is high and carbohydrates are limited. Insummary, the rationale of such diets is that intake of high amounts offat, whether long-chain or medium-chain triglycerides, can increaseblood ketone levels in the context of a highly-regimented diet in whichcarbohydrate levels are absent or limited. Limitation of carbohydrateand insulin are believed to prevent re-esterification in adipose tissue.In contrast to the prior art, the present invention provides for andclaims the administration of medium chain triglycerides outside of thecontext of the ketogenic diet. Furthermore, the EXAMPLES section belowprovides exemplary formulations which include carbohydrates.

Although the ketogenic diet has been known for decades, there does notappear to be any prior art teaching or suggesting that MCT therapy beused to treat Alzheimer's Disease or other cognitive disorders.

Additional metabolic adjuvants include energy enhancing compounds, suchas Coenzyme CoQ-10, creatine, L-carnitine, n-acetyl-carnitine,L-carnitine derivatives, and mixtures thereof. These compounds enhanceenergy production by a variety of means. Carnitine will increase themetabolism of fatty acids. CoQ10 serves as an electron carrier duringelectron transport within the mitochondria. Accordingly, addition ofsuch compounds with MCT will increase metabolic efficiency especially inindividuals who may be nutritionally deprived.

Administration of MCT, and especially triglycerides composed of C6 andC8 fatty acid residues, result in elevated ketone body levels even iflarge amounts of carbohydrate are consumed at the same time (foroverview see (Odle 1997); see also copending U.S. Patent ProvisionalPatent Application Ser. No. 60/323,995, “Drug Targets for Alzheimer'sDisease and Other Diseases Associated with Decreased NeuronalMetabolism,” filed Sep. 21, 2001). The advantages of the Applicant'sapproach are clear, since careful monitoring of what is eaten is notrequired and compliance is much simpler.

Further benefit can be derived from formulation of a pharmaceuticalcomposition comprising MCT and other therapeutic agents which are usedin the treatment of Alzheimer's Disease, Parkinson's Disease,Huntington's Disease, or epilepsy. Such therapeutic agents includeacetylcholinesterase inhibitors, acetylcholine synthesis modulators,acetylcholine storage modulators, acetylcholine release modulators,anti-inflammatory agents, estrogen or estrogen derivatives, insulinsensitizing agents, β-amyloid plaque removal agents (includingvaccines), inhibitors of β-amyloid plaque formation, γ-secretasemodulators, pyruvate dehydrogenase complex modulators, neurotrophicgrowth factors (e.g., BDNF), ceramides or ceramide analogs, and/or NMDAglutamate receptor antagonists for overview of such treatments see(Selkoe 2001; Bullock 2002)). While such treatments are still in theexperimental stage it is the novel insight of the present invention thatsaid treatments be advantageously combined with increased fattyacid/ketone body usage as described herein.

Advantages

From the description above, a number of advantages of the invention fortreating and preventing Alzheimer's Disease become evident:

-   -   (a) Prior art on AD has largely focused on prevention and        clearance of amyloid deposits. The role of these amyloid        deposits in AD remains controversial and may only be a marker        for some other pathology. The present invention provides a novel        route for treatment and prevention of AD based on alleviating        the reduced neuronal metabolism associated with AD, and not with        aspects of amyloid accumulation.    -   (b) Current treatments for AD are merely palliative and do not        address the reduced neuronal metabolism associated with AD.        Ingestion of medium chain triglycerides as a nutritional        supplement is a simple method to provide neuronal cells, in        which glucose metabolism is compromised, with ketone bodies as a        metabolic substrate.    -   (c) Increased blood levels of ketone bodies can be achieved by a        diet rich in medium chain triglycerides.    -   (d) Medium chain triglycerides can be infused intravenously into        patients or administered orally.    -   (e) Levels of ketone bodies can be easily measured in urine or        blood by commercially available products (e.g., Ketostix®,        Bayer, Inc.).

Accordingly, the reader will see that the use of medium chaintriglycerides (MCT) or fatty acids as a treatment and preventativemeasure of Alzheimer's Disease (AD) provides a novel means ofalleviating reduced neuronal metabolism associated with AD. It is thenovel and significant insight of the present invention that use of MCTresults in hyperketonemia which will provide increased neuronalmetabolism for diseases associated with reduced neuronal metabolism,such as AD, ALS, Parkinson's Disease and Huntington's Disease. Althoughthe description above contains many specificities, these should not beconstrued as limiting the scope of the invention but merely as providingillustrations for some of the presently preferred embodiments of thisinvention. For example, supplementation with MCT may prove moreeffective when combined with insulin sensitizing agents such as vanadylsulfate, chromium picolinate, and vitamin E. Such agents may function toincrease glucose utilization in compromised neurons and worksynergistically with hyperketonemia. In another example MCT can becombined with compounds that increase the rates of fatty acidutilization such as L-carnitine and its derivatives. Mixtures of suchcompounds may synergistically increase levels of circulating ketonebodies.

Thus the scope of the invention should be determined by the appendedclaims and their legal equivalents, rather than by the examples given.

REFERENCES

Throughout the specification, citations to a number of references havebeen made. Each of these references is incorporated by reference hereinin its entirety. Many of the references are summarized here:

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EXAMPLES

The following examples are offered by way of illustration and not by wayof limitation.

Example 1 Nutritional Drink

Nutritional drinks are prepared using the following ingredients:emulsified MCT 100 g/drink, L-carnitine 1 gram/drink, mix of dailyvitamins at recommended daily levels, and a variety of flavorings.

Example 2 Additional Formulations

Additional formulations can be in the form of Ready to Drink Beverages,Powdered Beverages, Nutritional drinks, Food Bars, and the like.Formulations for such are clear to those skilled in the art.

A. Ready to Drink Beverage

Ready to Drink Beverages are prepared using the following ingredients:emulsified MCT 5-100 g/drink, L-carnitine 250-1000 mg/drink, and avariety of flavorings and other ingredients used to increasedpalatability, stability, etc.

B. Powdered Beverages

MCT may be prepared in a dried form, useful for food bars and powderedbeverage preparations. A powdered beverage may be formed from thefollowing components: dried emulsified MCT 10-50 g, L-carnitine 250-500mg, sucrose 8-15 g, maltodextrin 1-5 g, flavorings 0-1 g.

C. Food Bar

A food bar would consist of: dried emulsified MCT 0.1-50 g, L-carnitine250-500 mg, glycerin 1-5 g, corn syrup solids 5-25 g, cocoa 2-7 g,coating 15-25 g.

D. Gelatin Capsules

Hard or soft gelatin capsules are prepared using the followingingredients: MCT 0.1-1000 mg/capsule, L-carnitine 250-500 mg/capsule,Starch, NF 0-600 mg/capsule; Starch flowable powder 0-600 mg/capsule;Silicone fluid 350 centistokes 0-20 mg/capsule. The ingredients aremixed, passed through a sieve, and filled into capsules.

E. Tablets

Tablets are prepared using the following ingredients: MCT 0.1-1000mg/tablet; L-carnitine 250-500 mg/tablet; Microcrystalline cellulose20-300 mg/tablet; Starch 0-50 mg/tablet; Magnesium stearate or stearateacid 0-15 mg/tablet; Silicon dioxide, fumed 0-400 mg/tablet; silicondioxide, colloidal 0-1 mg/tablet, and lactose 0-100 mg/tablet. Theingredients are blended and compressed to form tablets.

F. Suspensions

Suspensions are prepared using the following ingredients: 0.1-1000 mgMCT; 250-500 mg L-carnitine; Sodium carboxymethyl cellulose 50-700 mg/5ml; Sodium benzoate 0-10 mg/5 ml; Purified water 5 ml; and flavor andcolor agents as needed.

G. Parenteral Solutions

A parenteral composition is prepared by stirring 1.5% by weight of MCTand L-carnitine in 10% by volume propylene glycol and water. Thesolution is made isotonic with sodium chloride and sterilized.

Example 3 Treating Alzheimer's Disease with Medium Chain Triglycerides

The purpose of this study was to explore whether hyperketonemia improvescognitive functioning in individuals with memory disorders. The goal ofthis trial was to test the hypothesis that sustained elevation of serumbeta-hydroxybutyrate (BHB) levels through a large oral dose of mediumchain triglycerides will improve memory and attention performances inindividuals with Alzheimer's Disease and Mild Cognitive Impairment.

Participants

The sample consisted of 20 individuals with memory disorders recruitedfrom Western Washington. Potential subjects were excluded if they haddiabetes mellitus, hypoglycemia, major psychiatric disorders, or othermajor medical or neurological disorders such as hypertension,hypotension, cardiac problems, or COPD. In addition, patients wereexcluded from the study if they were taking medications with CNSeffects, such as anti-psychotics, anti-anxiolytics, andanti-hypertensives. However, subjects were allowed to participate ifthey were taking anti-depressants. Four participants were takinganti-depressants at the time of the study.

Table 1 describes the demographics of the sample. Fifteen subjects metNINCIDS/ADRDA criteria for probable AD. The remaining 5 subjects werediagnosed with Mild Cognitive Impairment, believed to be a prodromalphase of AD. Participants ranged in age from 61 to 84 years of age(mean=74.7), and 25% of the sample was female. The sample was welleducated with an average of 13.3 years of education. Ninety percent ofthe sample was Caucasian. Two non-Caucasian subjects were identified asAfrican-American and American Indian. Participants were typically in themild to moderate stages of dementia. The mean baseline MMSE was 22.2.Forty-seven percent of the participants had at least one apoE E-4allele.

TABLE 1 Sample Demographics and Medical Information Variable Mean SD Age74.7 6.7 Education 13.3 3.25 BMI 26.0 3.7 MMSE 22.2 5.5 n Sample % AD 1575 MCI 5 25 Female 5 25 E4+ 10/19 53 Non-Caucasian 2 10 Note: SD =Standard Deviation, BMI = Body Mass Index, MMSE = Mini-Mental StateExamination, E4+ = Subjects with at least one apoE E4 alleleProcedures

Subjects were recruited through medical clinics, senior centers, and adsin newspapers. Prospective subjects' medical histories and cognitivecomplaints were telephone screened by research nurses. Individuals werethen referred to the Memory Disorders Clinic at the VA Puget SoundHealth Care System (VAPSHCS) for clinical and/or neuropsychologicalevaluation. Routine laboratory assays and EKGs were completed to assistin diagnosis and determination of research inclusion.

The study was conducted with a randomized, double-blind placebocontrolled, crossover design. Initially, subjects were asked to come tothe VAPSHCS for three visits. During each visit, subjects received oneof two conditions in a randomized order: emulsified long chaintriglycerides as a placebo (232 ml of heavy whipping cream) or mediumchain triglycerides (MCT; 40 ml). NeoBee 895 (Stepan, Inc.) was used forMCTs. MCT were blended with 152 ml of heavy whipping cream. Vanilla andnon-caloric sweetener were added to the drink for taste.

Subjects arrived in the morning after a 12-hour fast and blood was drawnto determine BHB levels and apoE genotyping (first visit only). Subjectsthen consumed the blended test sample described above. About ninetyminutes later, a second blood draw occurred and a 30-minute cognitivetesting session ensued. A final blood draw was then completed. Studyvisits were conducted at least one week apart, and not more than fourweeks apart.

Neuropsychological Measures

Neuropsychological testing was performed by trained psychometrists usingstandardized procedures. A picture naming task, designed as a warm-uptest, was completed at the beginning of the 30-minute test battery toreduce subject anxiety. The cognitive protocol included paragraphrecall, the Stroop Color Word Interference Task, the Alzheimer's DiseaseAssessment Scale-Cognitive Subscale (ADAS-cog), and the Mini-MentalState Examination (MMSE).

The Logical Memory subtest of the Wechsler Memory Scale-III was used asthe model for the paragraph recall test. Subjects heard brief narrativescontaining 25 bits of information. They were asked to recall as muchinformation as possible, both immediately after hearing the story andagain after a 10 minute delay.

The Stroop Color Word Interference Task is a test of selectiveattention. The first two conditions require speeded reading of colorwords and speeded naming of colored blocks on a page. In the thirdcondition, color names are printed in discordant ink colors and subjectsare asked to state the color of the ink while inhibiting reading of thecolor words. Total reading time was recorded.

The ADAS-cog is a mental status test designed specifically to rate thecognitive functioning of patients with Alzheimer's Disease. Scores rangefrom 1 to 70 with higher scores indicating increased impairment.

The MMSE is a brief mental status test. Scores range from 0 to 30 withlower scores indicating increased impairment.

BHB Assays

Blood was processed immediately on the day of each subject's visit.Blood serum samples were kept in a −70° C. freezer until completion ofthe study. BHB levels were determined using a beta-hydroxybutyratediagnostic kit (Sigma Diagnostics, Inc.). All samples were included inthe assays and the lab was blinded to treatment conditions.

Results

Treatment Effects on BHB Levels

For BHB levels, a repeated measures ANCOVA was conducted with the apoEgenotype as the independent factor (E4+ vs. E4−), and condition(treatment vs placebo) and time of blood draw (0, 90 min, and 120 min)as repeated factors and BMI as a covariate. BHB levels increasedsignificantly with treatment (F[1, 15]=5.16, p<0.039), and there was asignificant difference in BHB levels at different time points (F[2,14]=5.22, p<0.01). Significant increases in BHB levels were observed90-minutes after treatment (p=0.007). In addition, there was asignificant interaction between E4 status and time of blood draw (F[2,14]=3.76, p=0.036). Contrasts revealed that the BHB levels for E4+subjects continued to rise between the 90-minute and 120-minute blooddraws in the treatment condition, while the BHB levels of E4− subjectsheld constant (p<0.003). Table 2 lists the BHB means and standarddeviations for each E4 group.

TABLE 2 Mean BHB Values by Treatment Condition and apoE E4 StatusBaseline 90′ 120′ E4 Status Mean SD Mean SD Mean SD Placebo E4− .04648.03565 .07525 .04780 .09241 .05803 E4+ .14013 .17946 .15589 .16760.18549 .18405 MCT Treatment E4− .04150 .02375 .53784 .31535 .51515.25437 E4+ .09504 .08286 .43022 .18648 .74142 .37714 Note: 90′ = Valuesdrawn 90 minutes after treatment; 120′ = Values drawn 120 minutes aftertreatmentTreatment Effects on Cognitive Performance

Repeated measures ANCOVAs were conducted with the apoE E4 allele as theindependent factor (E4+ vs. E4−) and condition (treatment vs placebo) asthe repeated factor, BHB levels at the time of cognitive testing as acovariate, and cognitive measures as the dependent variables. For theADAS-cog, subjects without the apoE-E4 allele showed improvementfollowing MCT administration, whereas E4+ subjects showed ADAS-cog TotalScores (lower scores indicate better performance) with slightly worseperformance (table 2). This pattern resulted in a significant conditionby E4 interaction (F[2, 14]=13.63, p=0.002). (see FIG. 2).

The repeated measures ANCOVA with paragraph recall as the dependentmeasure revealed a trend interaction between the effects of treatmentand BHB values measured just before testing (F[1, 14]=4.38, p=0.055).Subjects whose BHB levels were higher showed improved paragraph recallwith MCT administration.

What is claimed is:
 1. A method of treating loss of cognitive functioncaused by Alzheimer's disease or mild cognitive impairment, the methodcomprising: orally administering a dosage unit of medium chaintriglyceride (MCT) to a human patient in need thereof, wherein said MCTare administered at a dose of about 10 g per day to about 50 g per daycausing hyperketonemia in the patient, wherein the patient has a dietwherein carbohydrate intake is not restricted, resulting in ketonebodies being utilized for energy in the brain; and wherein the patient'sapolipoprotein E genotype is ApoE4(−).
 2. The method of claim 1, whereinthe dosage unit is given in a single dose.
 3. The method of claim 1,wherein the loss of cognitive function is caused by Alzheimer's Disease.4. The method of claim 1, wherein hyperketonemia results in a bloodlevel of D-beta-hydroxybutyrate of about 0.3 to 5 mM.
 5. The method ofclaim 1, wherein hyperketonemia results in a blood level ofD-beta-hydroxybutyrate of about 0.5 to 2 mM.
 6. The method of claim 1,wherein hyperketonemia results in a blood level ofD-beta-hydroxybutyrate of about 1 to 10 mM.